Method and device for mobile data offload

ABSTRACT

Embodiments provide a mobile data offload method for associating a mobile client device with a wireless access point. The method may include transmitting a first authentication request from the mobile client device to the wireless access point via a first network being a Cellular Wide Area radio communication network; transmitting a second authentication request from the mobile client device to the wireless access point via a second network being a Short Range radio communication network or a Metropolitan Area System radio communication network; transmitting an authentication response from the wireless access point to the mobile client device via the second network upon receiving at least one of the first authentication request and the second authentication request at the wireless access point, and associating the mobile client device with the wireless access point upon receiving the authentication response at the mobile client device.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of the Singapore patentapplication 201100315-9 filed on 17 Jan. 2011, the entire contents ofwhich are incorporated herein by reference for all purposes.

TECHNICAL FIELD

Embodiments relate generally to mobile data offload from one network toanother. Specifically, embodiments relate to mobile data offload from aCellular Wide Area radio communication network to another networkincluding a Short Range radio communication network or a MetropolitanArea System radio communication network.

BACKGROUND

The mobile data industry is evolving rapidly, resulting in exponentialgrowth in demand for bandwidth. Service providers have foreseen anincreasing data growth over the next few years. The growth in mobiledata usage is being fueled by growing 3G penetration, popularity ofsmartphones and USB dongles, advanced mobile applications and flat-ratedata plans. As a result, service providers are facing congested networkswhich are impacting their service delivery levels.

Many service providers are beginning to adopt a range of strategies,such as optimization of 3G networks using intelligent policy control,mobile data traffic offload, and transformation to 4G to reduce costsand alleviate congestion.

Mobile data offload, in particular 3G-WiFi offload, is becoming more andmore popular these days. Offload is the ability to move mobile datatraffic from one network to another in a way that is transparent to thesubscriber, which is a key component of an effective network congestionreduction strategy. Mobile data offload will reduce costs and improveeconomies of scale by balancing traffic requirements across networks.The cost savings are significant. Service providers deploying amulti-access offload strategy can expect savings in the range of 20 to25 percent per annum.

For example, AT&T has been in the forefront of using 3G-WiFi offload.AT&T hotspots automatically detect their subscribers and move their datatraffic to WiFi. The whole process is completely transparent to thesubscribers and the subscribers do not notice any difference.

Mobile data offload from 3G to WiFi presents a number of challenges toservice providers. First, service providers must ensure that subscribersreceive a consistent and comparable user experience regardless of accessnetwork, wherein service portability and continuity across multipleaccess networks is essential. Second, transparent sign-on is preferred,in which a single sign-on process is required to ensure seamless usageof various networks. Third, authentication access in non-3GPP networks,such as WiFi may not be easy when subscriber authentication data residesin the Home Location Register (HLR) in 3GPP networks. Fourth, smartphoneusers do not always have WiFi turned on due to the heavy battery drainon their handsets and network systems cannot force a device to switch onWiFi, which present challenges for service providers who want to offloadtraffic to WiFi. Fifth, the handset's connection manager requiresknowledge of WiFi hotspot locations, in particular those in the vicinityof high-traffic cell sites that typically experience congestion. Anoffload solution also needs to be subscriber-aware, including subscriberlocation as it relates to available hotspots. Sixth, Simultaneousoperation of WiFi and 3G is required, but not all handset manufacturersallow both 3G and WiFi to operate at the same time. In some cases, thiscan work but under a restricted condition where the WiFi acts as anAccess Point (AP). Seventh, WiFi range is short, mainly due to the powerof the WiFi transceiver on the handset. In most cases the link would behighly asymmetric, wherein the transmission from the access point wouldbe able to reach the handset but the transmission from the handset isunable to reach the AP. This restricts the offload to happen when theuser is static or very near to an AP. Eighth, there might be limitedaccess to WiFi network. In most cases, there will be many WiFi networksin the vicinity of the user but it would be difficult to capitalize onthese WiFi APs to provide 3G offload due to the lack of permission andnecessary software to enable the switching.

FIG. 1 illustrates the standard protocol exchange between a mobileclient and an AP in order for the mobile client to join a WiFi network.

As shown in FIG. 1, when the mobile client 101 tries to associate withthe AP 103, it sends a probe request 111 to the AP 103. The AP 103, uponreceiving the probe request 111, sends back a probe response 113 to themobile client 101. The mobile client 101 then sends an authenticationrequest 115 to the AP 103. The AP 103, upon receiving the authenticationrequest 115, sends back an authentication response 117 to the mobileclient 101. After authentication process, the mobile client 101 sends anassociation request 119 to the AP 103. The AP 103, upon receiving theassociation request 119, sends back an association response 121 to themobile client 101. Accordingly, the mobile client 101 is associated withthe wireless access point 103, and the mobile data offload from 3G toWiFi is enabled.

In the above process, the probe request 111 and the probe response 113are invoked depending on the scenario. Normally, probe request is usedwhen the mobile device proactively tries to search for APs to associatewith.

In practice, allowable transmission power levels of WiFi usually varyfrom region to region. For example, according to FCC rules, 4W EIRP forisotropic PMP mode is allowed for US. EIRP levels of 20 dBm are allowedin the EU. Based on these power levels, the range of a WiFi access pointoperating in the point to multipoint mode can reach a distance of about1 km. This would make it feasible for mobile network operators toinstall their own specialized WiFi APs. Long range WiFi nodes can beinstalled sparsely in the exterior of buildings. With the long rangeWiFi, the service provider need not depend on the public WiFi APs, whichis a nightmare when it comes to controlling quality of service, billing,installation and access management. Long range WiFi would thereforereduce cost and provide larger coverage foot print.

However, power levels in typical mobile client device, such assmartphones, are usually very low, which usually allow radio ranges ofup to about 50 m in the uplink. In that case, for example, the requests111, 115, 119 from the mobile client 101 in FIG. 1 may not be able toreach the AP 103 when the distance between the mobile client 101 and theAP 103 exceeds the uplink radio range, and therefore the 3G-WiFi offloadmay fail. The disparity in the radio ranges for the uplink and downlinktransmission to the mobile client remains a problem.

SUMMARY

Various embodiments provide a mobile data offload method for associatinga mobile client device with a wireless access point. The method mayinclude transmitting a first authentication request from the mobileclient device to the wireless access point via a first network being aCellular Wide Area radio communication network; transmitting a secondauthentication request from the mobile client device to the wirelessaccess point via a second network being a Short Range radiocommunication network or a Metropolitan Area System radio communicationnetwork; transmitting an authentication response from the wirelessaccess point to the mobile client device via the second network uponreceiving at least one of the first authentication request and thesecond authentication request at the wireless access point, andassociating the mobile client device with the wireless access point uponreceiving the authentication response at the mobile client device.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the sameparts throughout the different views. The drawings are not necessarilyto scale, emphasis instead generally being placed upon illustrating theprinciples of the invention. In the following description, variousembodiments are described with reference to the following drawings, inwhich:

FIG. 1 illustrates the standard protocol exchange between a mobileclient and an AP in order for the mobile client to join a WiFi network.

FIG. 2 shows a network architecture for mobile data offload inaccordance with various embodiments.

FIG. 3 shows a flowchart illustrating a mobile data offload method forassociating a mobile client device with a wireless access pointaccording to an embodiment.

FIG. 4 illustrates a mobile data offload method for associating a mobileclient device with a wireless access point according to anotherembodiment.

FIG. 5 shows a flowchart illustrating a mobile data offload method fordata transmission between a mobile client device and a wireless accesspoint according to an embodiment.

FIG. 6 illustrates a mobile data offload method for data transmissionbetween a mobile client device and a wireless access point according toanother embodiment.

FIG. 7 shows a wireless access point according to an embodiment.

FIG. 8 shows a schematic diagram of a mobile client device according toan embodiment.

DESCRIPTION

Various embodiments address the unfavorable uplink radio ranges toprovide a more reliable offload solution to associate the mobile clientwith the APs.

Various embodiments provide a more reliable data transmission whenmobile data traffic is offloaded to another network, e.g. a Short Rangeradio communication network or a Metropolitan Area System radiocommunication network.

Various embodiments provide a reliable mobile data offload method, whichalso achieves an improved coverage and availability of a Short Rangeradio communication network or a Metropolitan Area System radiocommunication network for offloading.

Embodiments described below in context of the mobile data offload methodare analogously valid for the respective devices for implementing theoffload method, and vice versa.

In this context, the mobile client device, the wireless access point andthe offload server as described in this description may include a memorywhich is for example used in the processing carried out in thesedevices. A memory used in the embodiments may be a volatile memory, forexample a DRAM (Dynamic Random Access Memory) or a non-volatile memory,for example a PROM (Programmable Read Only Memory), an EPROM (ErasablePROM), EEPROM (Electrically Erasable PROM), or a flash memory, e.g., afloating gate memory, a charge trapping memory, an MRAM(Magnetoresistive Random Access Memory) or a PCRAM (Phase Change RandomAccess Memory).

In this context, the mobile client device, the wireless access point andthe offload server as described in this description may be or mayinclude one or more circuits configured to perform the respectiveprocessing, respectively.

In an embodiment, a “circuit” may be understood as any kind of a logicimplementing entity, which may be special purpose circuitry or aprocessor executing software stored in a memory, firmware, or anycombination thereof. Thus, in an embodiment, a “circuit” may be ahard-wired logic circuit or a programmable logic circuit such as aprogrammable processor, e.g. a microprocessor (e.g. a ComplexInstruction Set Computer (CISC) processor or a Reduced Instruction SetComputer (RISC) processor). A “circuit” may also be a processorexecuting software, e.g. any kind of computer program, e.g. a computerprogram using a virtual machine code such as e.g. Java. Any other kindof implementation of the respective functions which will be described inmore detail below may also be understood as a “circuit” in accordancewith an alternative embodiment.

One embodiment is directed to a mobile data offload method forassociating a mobile client device with a wireless access point. Themethod may include transmitting a first authentication request from themobile client device to the wireless access point via a first networkbeing a Cellular Wide Area radio communication network; transmitting asecond authentication request from the mobile client device to thewireless access point via a second network being a Short Range radiocommunication network or a Metropolitan Area System radio communicationnetwork; transmitting an authentication response from the wirelessaccess point to the mobile client device via the second network uponreceiving at least one of the first authentication request and thesecond authentication request at the wireless access point, andassociating the mobile client device with the wireless access point uponreceiving the authentication response at the mobile client device.

In an embodiment, transmitting the first authentication request via thefirst network may include transmitting the first authentication requestfrom the mobile client device to an offload server via the firstnetwork; and transmitting the first authentication request from theoffload server to the wireless access point via the first network.

According to an embodiment, the sequence of transmitting the firstauthentication request and transmitting the second authenticationrequest may be interchangeable.

In one embodiment, associating the mobile client device with thewireless access point may include, upon receiving the authenticationresponse at the mobile client, transmitting a first association requestfrom the mobile client device to the wireless access point via the firstnetwork and transmitting a second association request from the mobileclient device to the wireless access point via the second network.Associating the mobile client device with the wireless access point mayfurther include, upon receiving at least one of the first associationrequest and the second association request at the wireless access point,transmitting an association response from the wireless access point tothe mobile client via the second network.

According to an embodiment, transmitting the first association requestvia the first network may include transmitting the first associationrequest from the mobile client device to an offload server via the firstnetwork; and transmitting the first association request from the offloadserver to the wireless access point via the first network.

The sequence of transmitting the first association request andtransmitting the second association request may be interchangeable.

In another embodiment, after transmitting the authentication responsefrom the wireless access point for a predetermined time period, one ormore association responses are transmitted continuously from thewireless access point to the mobile client via the first network. Anassociation request is transmitted from the mobile client device to thewireless access point. It is determined whether the mobile client devicereceives the one or more association responses after the transmission ofthe association request; and if it is determined that the mobile clientdevice receives the one or more association responses after thetransmission of the association request, the mobile client device isassociated with the wireless access point.

According to an embodiment, before transmitting the first authenticationrequest and the second authentication request from the mobile clientdevice, the method may further include transmitting a first proberequest from the mobile client device to the wireless access point viathe first network; transmitting a second probe request from the mobileclient device to the wireless access point via the second network; andtransmitting a probe response from the wireless access point to themobile client via the second network upon receiving at least one of thefirst probe request and the second probe request at the wireless accesspoint.

In an embodiment, transmitting the first probe request via the firstnetwork may include transmitting the first probe request from the mobileclient device to an offload server via the first network; andtransmitting the first probe request from the offload server to thewireless access point via the first network.

The Cellular Wide Area radio communication network in this descriptionmay include but is not limited to a communication network based on oneof the following technologies, e.g. a Global System for MobileCommunications (GSM) radio communication technology, a General PacketRadio Service (GPRS) radio communication technology, an Enhanced DataRates for GSM Evolution (EDGE) radio communication technology, a ThirdGeneration Partnership Project (3GPP) radio communication technology(e.g. UMTS (Universal Mobile Telecommunications System) (e.g., W-CDMA(Wideband Code Division Multiple Access)), FOMA (Freedom of MultimediaAccess), 3GPP LTE (Long Term Evolution), 3GPP LTE Advance (Long TermEvolution Advance)), and/or a Fourth Generation (4G) radio communicationtechnology.

The Short Range radio communication network in this description mayinclude but is not limited to one of the following communicationnetworks, e.g. Wireless Local Area Network (LAN) radio communication(e.g. according to an IEEE 802.11 (e.g. IEEE 802.11n) radiocommunication standard, e.g. WiFi), Bluetooth radio communication.

The Metropolitan Area System radio communication network in thisdescription may include but is not limited to one of the followingcommunication network, e.g. wireless Metropolitan Area Network (MAN)radio communication, Worldwide Interoperability for Microwave Access(WiMax) (e.g. according to an IEEE 802.16 radio communication standard),Wireless Broadband (WiBro).

Another embodiment is directed to a mobile client device for carryingout the offload method described in the above embodiments. The mobileclient device may include a first interface providing access to a firstnetwork being a Cellular Wide Area radio communication network; a secondinterface providing access to a second network being a Short Range radiocommunication network or a Metropolitan Area System radio communicationnetwork; and a transceiver. The transceiver is configured to transmitone or more probe requests, authentication requests and/or associationrequests to a wireless access point through the first interface via thefirst network and to transmit the one or more requests to the wirelessaccess point throught the second interface via the second network,respectively, and the transceiver is configured to receive responsesfrom the wireless access point through the second interface via thesecond network.

In one embodiment, the mobile client device may further include adetermining circuit configured to determine whether the mobile clientdevice receives an association response after the transmission of theassociation request according to the method described above.

Another embodiment is directed to an offload server carrying out theoffload method described in the above embodiments. The offload servermay include a transceiver configured to receive a probe request, anauthentication request and/or an association request from a mobileclient device via a Cellular Wide Area radio communication network; andto transmit the received probe request, the received authenticationrequest and/or the received association request to a wireless accesspoint via the Cellular Wide Area radio communication network.

A further embodiment is directed to a wireless access point carrying outthe offload method described in the above embodiments.

The wireless access point may include a plurality of wirelesstransceivers. The wireless transceivers are configured to receive one ormore probe requests, authentication requests and/or association requestsfrom an offload server via a first network and/or from a mobile clientdevice via a second network, and the wireless transceivers areconfigured to transmit a probe response, an authentication responseand/or an association response to the mobile client device via thesecond network. The first network may be a Cellular Wide Area radiocommunication network, and the second network may be a Short Range radiocommunication network or a Metropolitan Area System radio communicationnetwork.

In an embodiment, the wireless access point is a long range WiFi accesspoint providing a radio range of more than 100 m. Examples of the radioranges may include 100 m, 200 m, 500 m, 800 m, etc. In anotherembodiment, the wireless access point is a long range WiFi access pointproviding a radio range of more than 1 km. Depending on the powerlimits, and if regulators allow more power, the wireless access pointmay provide an even longer radio range, e.g. beyond 1 km, 2 km, 5 km, 10km, 50 km, etc. in other embodiments.

In one embodiment, the wireless access point may include a virtualwireless transceiver configured to route the probe requests,authentication requests and/or association requests to a desiredwireless transceiver determined out of the plurality of wirelesstransceivers.

In another embodiment, the wireless access point may include a driverconfigured to route the probe requests, authentication requests and/orassociation requests to a desired wireless transceiver determined out ofthe plurality of wireless transceivers.

In the above embodiments, the desired wireless transceiver may bedetermined based on the location of mobile client device.

Another embodiment is directed to a mobile data offload method. Themethod may include transmitting uplink data from a mobile client devicevia a first network being a Cellular Wide Area radio communicationnetwork, and transmitting downlink data to the mobile client device viaa second network being a Short Range radio communication network or aMetropolitan Area System radio communication network.

In an embodiment, the method further include initiating the transmissionof downlink data from a wireless access point to the mobile clientdevice using a two-way handshake or a four-way handshake.

In one embodiment, the method may include transmitting a data packetfrom the wireless access point to the mobile client device via thesecond network, and faking an ACK packet at the wireless access point asif the ACK packet originates from the mobile client device. The fackedACK packet is sent to a desired wireless transceiver of the wirelessaccess point.

In another embodiment, the method may further include, beforetransmitting the data packet, transmitting a RTS (Ready to send) messagefrom the wireless access point to the mobile client device via thesecond network. A CTS (Clear to send) message is faked at the wirelessaccess point as if the CTS message originates from the mobile clientdevice; and the faked CTS message is sent to a desired wirelesstransceiver of the wireless access point.

According to an embodiment, the method may further include interceptingtransmission of a data response packet from the mobile client device tothe wireless access point via the second network, upon receiving thedata packet at the mobile client device. The data response packet isthen transmitted from the mobile client device to the wireless accesspoint via the first network.

According to another embodiment, the method may include intercepting, atthe mobile client device, the transmission of the uplink data via thesecond network.

In an embodiment, transmitting the data response packet or the uplinkdata via the first network may include tunneling the data responsepacket or the uplink data to the wireless access point using a tunnelingprotocol.

Another embodiment is directed to a mobile client device. The mobileclient device may include a first interface providing access to a firstnetwork being a Cellular Wide Area radio communication network; a secondinterface providing access to a second network being a Short Range radiocommunication network or a Metropolitan Area System radio communicationnetwork; and a transceiver. The transceiver is configured to transmituplink data to the wireless access point through the first interface viathe first network, and to receive downlink data from the wireless accesspoint through the second interface via the second network. The mobileclient device may further include an interception circuit configured tointercept uplink data to be transmitted to the wireless access point viathe second network.

A further embodiment is directed to a wireless access point, including aplurality of wireless transceivers configured to transmit downlink datato a mobile client device via a Short Range radio communication networkor a Metropolitan Area System radio communication network. The wirelessaccess point may further include a virtual wireless transceiverconfigured to fake one or more packets as if the packets originate fromthe mobile client device, and to send the faked packets to a desiredwireless transceiver determined out of the plurality of wirelesstransceivers.

Another embodiment is directed to a wireless access point, including aplurality of wireless transceivers configured to transmit downlink datato a mobile client device via a Short Range radio communication networkor a Metropolitan Area System radio communication network. The wirelessaccess point may further include a driver configured to fake one or morepackets as if the packets originate from the mobile client device, andto send the faked packets to a desired wireless transceiver determinedout of the plurality of wireless transceivers.

FIG. 2 shows a network architecture for mobile data offload inaccordance with various embodiments.

The mobile data offload from a first network to a second network inaccordance with various embodiments is provided.

The first network may be a Cellular Wide Area radio communicationnetwork. As described above, the Cellular Wide Area radio communicationnetwork may include but is not limited to communication networks basedon the following technology, e.g. GSM, GPRS, EDGE, 3GPP radiocommunication technology (e.g. UMTS (e.g. W-CDMA), FOMA, 3GPP LTE, 3GPPLTE Advance), and/or 4G.

The second network may be a Short Range radio communication network or aMetropolitan Area System radio communication network.

As described above, the Short Range radio communication network mayinclude but is not limited to the following communication networks, e.g.Wireless LAN (e.g. according to an IEEE 802.11 (e.g. IEEE 802.11n) radiocommunication standard, e.g. WiFi), Bluetooth.

As described above, the Metropolitan Area System radio communicationnetwork may include but is not limited to the following communicationnetworks, e.g. wireless MAN, WiMax, WiBro.

In this example, the mobile data offload is described in the context of3G-WiFi offload. However, it is to be noted that the mobile data offloadof various embodiments can be applied for offload from other types ofCellular Wide Area radio communication network to other types of ShortRange radio communication network or Metropolitan Area System radiocommunication network.

A mobile client 201 may include two or more interfaces for networkaccess. In an embodiment, the mobile client 201 includes a firstinterface, e.g. a 3G interface 203, enabling access to a Cellular WideArea radio communication network, e.g. a 3G network. The mobile client201 further includes a second interface providing access to a ShortRange radio communication network or a Metropolitan Area System radiocommunication network, such as Wireless LAN or Wireless MAN. In thisembodiment, the second interface is a WiFi (also referred to as802.11a/b/g/n) interface 205. Examples of the mobile client device 201include but are not limited to handphones, smartphones, tabletcomputers, PDA and handheld game consoles.

In FIG. 2, the mobile client device 201 connects to the 3G network in astandard manner via the 3G RAN (Radio Access Network) 221. The mobileclient device 201 connects to a desired WiFi AP 211 selected out of aplurality of WiFi APs through its WiFi interface 205 using the standardpoint-to-multipoint protocol. In the example of FIG. 2, the distancebetween the mobile device 201 and the WiFi AP 211 is depicted as 1 km,in which the WiFi AP 211 is a long range WiFi AP. However, anycommunication link distance shorter than 1 km is also possible in otherembodiments. When the distance between the mobile client device 201 andthe WiFi AP 211 is long, the mobile client 201 may receive downlinkpackets/frames from the WiFi AP 211, but the uplink transmission to theWiFi AP 211 may not be successful due to the RF power level of themobile client 201 using the conventional offload method, as discussedabove. In an embodiment, the WiFi AP 211 is provided with extra featuresto handle the asymmetrical WiFi uplink and downlink communication, aswill be described in detail below.

In FIG. 2, a SGSN (Serving GPRS Support Node) 223 is provided betweenthe 3G RAN 221 and a GGSN (Gateway GPRS Support Node) 225 for deliveryof data packets from and to the mobile client device 201. The GGSN 225is connected to the WiFi AP 211 via the Internet. The GGSN 225 may alsobe connected directly to the Wireless APs 211 through an optional link227 as shown in FIG. 2.

A 3G-WiFi offload server 231 is also provided, which may be located onthe Internet or located in the 3G network being connected with the GGSN225 through an optional link 232. The 3G-WiFi offload server 231 isconfigured to aid in the coordination of the uplink and downlinkcommunication between the WiFi AP 211 and the mobile client 201. In anembodiment, the 3G-WiFi offload server 231 may be co-located with thedistributed long range WiFi APs 211.

The mobile data offload method between a Cellular Wide Area radiocommunication network and another network including a Short Range radiocommunication network or a Metropolitan Area System radio communicationnetwork in accordance with various embodiments as described below isimplemented in the architecture of FIG. 2.

FIG. 3 shows a flowchart illustrating a mobile data offload method forassociating a mobile client device with a wireless access pointaccording to an embodiment.

At 301, a first authentication request is transmitted from the mobileclient device to the wireless access point via a first network, whereinthe first network is a Cellular Wide Area radio communication network.In an embodiment, transmitting the first authentication request via thefirst network may include transmitting the first authentication requestfrom the mobile client device to an offload server via the firstnetwork, and transmitting the first authentication request from theoffload server to the wireless access point via the first network.

At 303, a second authentication request is transmitted from the mobileclient device to the wireless access point via a second network, whereinthe second network is a Short Range radio communication network or aMetropolitan Area System radio communication network.

At 305, an authentication response is transmitted from the wirelessaccess point to the mobile client device via the second network, uponreceiving at least one of the first authentication request and thesecond authentication request at the wireless access point.

At 307, the mobile client device is associated with the wireless accesspoint, upon receiving the authentication response at the mobile clientdevice.

The sequence of transmitting the first authentication request at 301 andtransmitting the second authentication request at 303 may beinterchangeable according to an embodiment.

In one embodiment, associating the mobile client device with thewireless access point at 307 may include transmitting a firstassociation request from the mobile client device to the wireless accesspoint via the first network and transmitting a second associationrequest from the mobile client device to the wireless access point viathe second network, upon receiving the authentication response at themobile client. Upon receiving at least one of the first associationrequest and the second association request at the wireless access point,an association response is transmitted from the wireless access point tothe mobile client via the second network.

In another embodiment, associating the mobile client device with thewireless access point at 307 may be based on an estimation of the timewhen the mobile client needs to initiate the association session. Aftertransmitting the authentication response from the wireless access pointat 305 for a predetermined time period, one or more associationresponses is transmitted continuously from the wireless access point tothe mobile client via the second network. An association request istransmitted from the mobile client device to the wireless access point.It is then determined whether the mobile client device receives the oneor more association responses after the transmission of the associationrequest; and if it is determined that the mobile client device receivesthe one or more association responses after the transmission of theassociation request, the mobile client device is associated with thewireless access point.

In a further embodiment, before transmitting the first authenticationrequest at 301 and transmitting the second authentication request at 303from the mobile client device, a Probe session may be initiated betweenthe mobile client device and the wireless access point. In anembodiment, a first probe request is transmitted from the mobile clientdevice to the wireless access point via the first network, and a secondprobe request is transmitted from the mobile client device to thewireless access point via the second network. Upon receiving at leastone of the first probe request and the second probe request at thewireless access point, a probe response is transmitted from the wirelessaccess point to the mobile client via the second network, indicatingthat the mobile client device and the wireless access point may proceedwith the authentication session.

FIG. 4 illustrates a mobile data offload method for associating a mobileclient device with a wireless access point according to anotherembodiment.

When a mobile client 401 wants to offload the data to WiFi, it sends afirst probe request in a message 411 to a 3G-WiFi offload server 405 viathe 3G network. The first probe request is processed by the 3G-WiFioffload server 405 which may reside in the 3G network or outside the 3Gnetwork. The first probe request may include information about thelocation of the mobile client 401. The location of the mobile client 401may be obtained in several ways, including 3G base stationtriangulation, GPS, etc. In an alternative embodiment, instead of beingcoded and carried in the probe request message 411, the location of themobile client 401 may be requested by the 3G-WiFi offload server 405from the 3G network. Location information of the mobile client 401 isessential in deciding which AP or which transceiver at the AP should beused to service the client. The location information will be sent to theAP 405 so that the AP 405 will be able to decide which transceiver atthe AP is to be used.

The mobile client 401 may also send a second probe request in a message413 to a wireless AP 403 through the WiFi interface on the mobile client401.

Depending on the configuration (e.g. the software configuration) of themobile client device 401, the sequence of sending the first proberequest and the second probe request are interchangeable. In anembodiment, the mobile client device 401 is provided with a softwaremodule which actively sniffs for the messages, e.g. the message 413including the second probe request, that are being sent out through theWiFi interface of the mobile client device 401. Once the probe requestmessage 413 has been sent out, the software module on the mobile clientdevice 401 may then initiate the transmission of the first probe requestmessage 411 to the 3G network after the transmission of the second proberequest message 413. The second probe request message 413 in FIG. 4 isdepicted with a short and slashed arrow, indicating that the message 413might not reach the AP via the uplink wireless link due to the shortradio ranges in the uplink.

After receiving the first probe request message 411, the 3G-WiFi offloadserver 405 sends the first probe request in a message 415 to the AP 403.When the AP 403 receives the message 415 via the 3G network, the AP 403channels the message 415 to a specific WiFi transceiver desired to servethe mobile client 401. The desired WiFi transceiver is determined basedon the location of the mobile client device 401, wherein the locationinformation may be included in the message 415.

The message 415 may be routed to a desired WiFi transceiver at the AP403. The AP 403 may include a plurality of transceivers to cater forcoverage in different directions. In an embodiment, a WiFi transceiverwith its antenna pointing to the mobile client 401 is determined to be adesired WiFi transceiver and will be selected for use. In oneembodiment, the AP 403 may include a virtual transceiver configured toroute the message 415 directly to the intended WiFi transceiver via theradio link. In another embodiment, the AP 403 may include an internaldevice driver configured to route the message 415 to the intended WiFitransceiver. When the WiFi transceiver of the AP 403 receives either oneof the second probe request 413 or the probe request message 415, it maygenerate and send a probe response in a message 417 to the mobile client401. The probe response message 417 will reach the mobile client 401 viathe long distance link.

After the probe response message 417 is received by the mobile client401, the mobile client 401 may send a first authentication request in amessage 421 to the 3G-WiFi offload server 405 via the 3G network.Similar to the probe request, the mobile client 401 may be configured tosniff the activity on the WiFi interface and wait for the WiFi device tosend out a second authentication request in a message 423 via the WiFinetwork before initiating the transmission of message 421, according toan embodiment. In another embodiment, the mobile client 401 may initiatethe transmission of message 421 before the transmission of message 423,if the mobile client 401 has a better control of the WiFi managementexchange. The second authentication request message 423 is depicted witha short and slashed arrow, indicating that the message 423 might notreach the AP via the uplink wireless link due to the short radio rangesin the uplink.

When the first authentication message 421 is received by the 3G-WiFioffload server 405, it may be routed to the AP 403 in a message 425. Inone embodiment, the AP 403 may include a virtual transceiver which actson behalf of the mobile client 401 to fake the authentication requestvia the radio interface. In another embodiment, the AP 403 may include asoftware module, e.g. an internal driver, to directly send theauthentication request to the appropriate WiFi transceiver via thenetworking stack. Upon receiving the authentication request, the WiFitransceiver of the AP 403 transmits an authentication response in amessage 427 to the mobile client 401 via the long distance link.

Once authentication is done, the association process may be carried outto associate the mobile client 401 with the AP 403. Similar to the aboveProbe and Authentication sessions, the mobile client 401 may send afirst association request in a message 431 to the offload server 405 viathe 3G network, and send a second association request in a message 433to the AP 403 via the WiFi network. In one embodiment, the message 431may be transmitted before the message 433. In another embodiment, themobile client 401 may be configured to sniff the activity of the WiFiinterface and wait for the transmission of the association requestmessage 433 before transmitting the message 431. The second associationrequest message 433 is depicted with a short and slashed arrow,indicating that the message 433 might not reach the AP via the uplinkwireless link due to the short radio ranges in the uplink.

The offload server 405 forwards the received first association requestin a message 435 to the AP 403. In one embodiment, the AP 403 mayinclude a virtual transceiver configured to forward the associationrequest message 433 or 435 to the desired WiFi transceiver. In anotherembodiment, the association request message 433 or 435 may be sentdirectly to the WiFi device driver via the networking stack. Anassociation response in a message 437 is finally sent to the mobileclient 401 to associate the mobile client device 401 with the AP 403.Once the mobile client device 401 is associated with the AP 403, it isready to receive data via the WiFi network.

In an embodiment, the three message exchanges, including proberequest—probe response, authentication request—authentication responseand association request—association response above, may have theirassociated timers. In an exemplary implementation, the timers may be setto 5 seconds. It is essential for the round trip request—response forthese three pairs of message exchange to meet the timing requirement. Ifthe timing is not met, the message exchanges may be retried.

In the above embodiments, the mobile client device 401 may have todepend a lot on the packet sniffing approach. In another embodiment, analternative approach based on timing the response of the messages fromthe AP 405 at the appropriate time is provided. For example, it isassumed that the user or a client software at the mobile client device401 is able to initiate the authentication process. Once the mobileclient 401 sends out the authentication message 423 through WiFi, theclient device 401 may also send the authentication message 421 via 3G tothe AP 403. The AP 403 may then respond with the authentication responsemessage 427 via WiFi. The AP 403 may anticipate the sending of theassociation messages 421, 423 from the mobile client 401. This iscarried out by estimating the time that the client 401 needs to initiatethe association request after receiving the authentication responsemessage 427. The AP 403 may then send one or several associationresponse messages 437 continuously to help the client 401 associate. Ifthe client 401 receives association response messages 437 after theassociation request messages 421, 423 have been sent out, the mobileclient 401 may be associated with the AP 403. If the associationresponse message 427 is received before the association request messages421, 423 are sent out, the mobile client 401 may receive a responsemessage indicating failure of the association process. When the overallassociation process fails, the entire process starting fromauthentication or association may be repeated.

In the above embodiments, the WiFi AP 403 may be a long range WiFi APwith a radio range of more than 100 m. For example, the WiFi AP 403 mayprovide a radio range of 100 m, 200 m, 500 m, or 800 m, etc. In otherexamples, the WiFi AP 403 may provide a longer radio range, e.g. beyond1 km, 2 km, 5 km, 10 km, 50 km, etc. depending on the power limits inother embodiments.

In accordance with the embodiments, the request messages 411, 421, 431in the uplink are transmitted via the 3G network. Compared withconventional offload method to transmit the association request via theWiFi in which the association request may not reach the WiFisuccessfully, the embodiments improves the uplink transmission at a longdistance from the WiFi AP and ensures a reliable offload process toassociate the mobile client with the WiFi AP.

In the above embodiments described with reference to FIG. 4, the messageexchange between the mobile client and the AP is described in the casewherein three management protocol exchanges of Probe, Authentication andAssociation are included. It is understandable that protocol exchangesof only Authentication and Association may be used in anotherembodiment, for example, when the mobile client is not proactivelysearching for APs to associate with. In other embodiments, it is alsopossible that the protocol exchanges of Association message is used, forexample, when the mobile client has been authenticated to the AP inanother way.

After the mobile client is associated with the AP according to theembodiments above, the data transmission may be offloaded to the ShortRange radio communication network or the Metropolitan Area System radiocommunication network.

FIG. 5 shows a flowchart illustrating a mobile data offload method fordata transmission between a mobile client device and a wireless accesspoint according to an embodiment.

At 501, uplink data is transmitted from a mobile client device via afirst network, e.g. to a wireless AP. The first network is a CellularWide Area radio communication network.

At 503, downlink data is transmitted from the wireless AP to the mobileclient device via a second network, wherein the second network is aShort Range radio communication network or a Metropolitan Area Systemradio communication network.

In accordance with the above embodiment, only downlink data transmissionis offloaded to the second network, e.g. WiFi, since the downlink datatransmission from the wireless AP is usually stable and reliable evenwhen the mobile client device is at a long distance from a long rangewireless AP. The uplink data transmission is still performed via theCellular Wide Area radio communication network, which avoids unreliableuplink transmission via the second network due to the short radio rangeof the mobile client device in the uplink. According to the aboveembodiment, the uplink and downlink traffic between 3G and WiFi networkis split, wherein the use of the 3G network is critical and mainly usedfor uplink data transfer as well as critical control messages. Inaddition, the justification for higher service charges from the MNC'sview is stronger especially if the 3G network and the long rangeinfrastructure WiFi owned/managed by the MNC is used.

In an embodiment, the transmission of downlink data from the wirelessaccess point to the mobile client device at 503 is initiated using atwo-way handshake or a four-way handshake.

In an embodiment wherein the two-way handshake is used, the transmissionof downlink data may include transmitting a data packet from thewireless access point to the mobile client device via the secondnetwork. At the wireless access point, an ACK packet may be faked as ifthe ACK packet originates from the mobile client device. The faked ACKpacket is then sent to a desired wireless transceiver of the wirelessaccess point.

In another embodiment wherein the four-way handshake is used, a RTS(Ready to send) message may be transmitted from the wireless accesspoint to the mobile client device via the second network, before thetransmission of the data packet as described above. A CTS (Clear tosend) message is faked at the wireless access point as if the CTSmessage originates from the mobile client device. The faked CTS messageis then sent to a desired wireless transceiver of the wireless accesspoint.

In the embodiments using two-way handshake or four-way handshake, uponreceiving the data packet at the mobile client device, the transmissionof a data response packet from the mobile client device to the wirelessaccess point via the second network may be intercepted. The dataresponse packet is instead transmitted from the mobile client device tothe wireless access point via the Cellular Wide Area radio communicationnetwork. In an embodiment, transmitting the data response packet via theCellular Wide Area radio communication network may include tunneling thedata response packet to the wireless access point using a tunnelingprotocol. The process of interception and re-transmission via theCellular Wide Area radio communication network may also be similarlyapplied to the transmission of uplink data.

FIG. 6 illustrates a mobile data offload method for data transmissionbetween a mobile client device and a wireless access point according toanother embodiment.

For illustration purposes, the first network is selected as the 3Gnetwork and the second network is selected as the WiFi network. It isunderstandable that other types of Cellular Wide Area radiocommunication network and Short Range radio communication networks orMetropolitan Area System radio communication networks may be used inother embodiments.

Data exchange in WiFi or 802.11 is normally based on a four-wayhandshake or a two-way handshake. According to an embodiment, the dataexchange between the mobile client 601 and the WiFi AP 603 isasymmetrical when the mobile client 601 and the AP 603 are far apartfrom each other. In accordance with an embodiment, the uplink data istransmitted via 3G interface, while the downlink data is transmitted viaWiFi interface.

In the following example, the networking “Ping” utility is used toillustrate the data exchange. When the AP 603 pings the client 601, itwill send a ping request to the client 601. In the embodiment of FIG. 6,the AP 603 initiates a 4 way handshake and sends an RTS (Ready to send)message 611 to the mobile client 601 at the link layer.

The mobile client device 603 may reply with a CTS (Clear to send)message 613 via the WiFi. However, the CTS message 613 may not arrive atthe AP 603 due to the long distance between the client 601 and the AP603. In an embodiment, the AP 603 may include a virtual WiFi interface,also referred to as a virtual transceiver, used to send a CTS message615 to the intended WiFi interface at the AP 603. The MAC address of thevirtual interface may be configurable and mimics the MAC address of theclient 601, such that the CTS message 615 is a faked CTS message as iforiginating from the client 601. The intended WiFi transceiver of the AP603 is then be fooled to believe that the CTS message 615 has been sentby the client 601.

The AP 603 then sends out the Ping request data message 617 to theclient 617 via WiFi. The client 601 receives the Ping request datamessage 617 and processes the message 617 accordingly. The client 601may send an ACK message 619 to the AP 603 via WiFi, which ACK message619 may not reach the AP 603 due to the distance between the client 601and the AP 603. On the AP 603, the virtual transceiver may mimic the ACKmessage 619 and send the faked ACK message 621 to the intended WiFitransceiver at the AP 603.

In the uplink direction, the response message 623 of the ping packet isintercepted by the mobile client 601 (e.g. by a software module of themobile client) at the networking layer before it can be sent to the WiFiinterface of the mobile client 601. The Ping response packet 623 is sentvia the 3G interface of the mobile 601 to the AP 603. In an embodiment,the Ping response message 623 is transmitted to a 3G-WiFi offload server605 via the 3G network, and the offload server 605 transmits the Pingresponse packet in a message 625 to the AP 603 via the 3G network. Theresponse message may be tunneled to the intended AP 603 via a tunnelingprotocol.

The above method may also be used to perform a TCP like session betweenthe mobile client 601 and the AP 603, creating a reliable link betweenthese two devices. Any packet, such as TCP ACK packet, that is destinedto the AP in the uplink may be captured by the mobile client 601 (e.g.by a software module of the mobile client) and tunneled via the 3Ginterface to the AP 603. In this manner, a reliable packet deliverymechanism can be achieved.

In another embodiment, the AP 603 may initiate a 2-way handshake. In anembodiment, the AP 603 may be modified in such a way that an incomingACK message is faked at the MAC layer of the WiFi interface at the AP603, without the need to using a virtual driver to fool the transceiverat the AP 603 that a packet originating from the mobile client 601 hasbeen received.

FIG. 7 shows a wireless access point according to an embodiment.

The wireless access point 700 may include a CPU 701, which acts as anaddressable device and may include several services to handle thecommunication between the access point 700 and a mobile client device.

The wireless access point 700 may include a plurality of wirelesstransceivers, e.g. WiFi transceivers 703, which are connected to aplurality of antennas, respectively. In an example, the WiFitransceivers 703 are connected to sector antennas 705.

In an embodiment, the wireless access point 700 may include anadditional WiFi transceiver 711 acting as a virtual transceiver 711 forthe distant mobile client. The virtual transceiver 711 may aid in theuplink transmission to carry out various WiFi functions, such asAssociation, Authentication, Probes, 4-way RTS-CTS-DATA-ACK handshakeand 2-way DATA-ACK handshake, as described in various embodiments above.The operation of the virtual transceiver 711 is controlled by the WiFiAP 700, and is coordinated through the protocol exchange between themobile device and WiFi AP that could go through the 3G network as wellas the WiFi network. The virtual transceiver 711 may route RF signal viaa bank of RF switch 713 to the multiple WiFi transceivers 703.

In one embodiment, the wireless access point 700 may be used in themobile data offload method for associating the mobile client device tothe access point as described in FIGS. 3 and 4 above.

The plurality of WiFi transceivers 703 may be configured to receive oneor more probe requests, authentication requests and/or associationrequests from an offload server via a first network and/or from a mobileclient device via a second network. The first network may be a CellularWide Area radio communication network, and the second network may be aShort Range radio communication network or a Metropolitan Area Systemradio communication network as described above. The WiFi transceivers703 may also be configured to transmit a probe response, anauthentication response and/or an association response to the mobileclient device via the second network.

In an embodiment, the virtual transceiver 711 may be used to route thevarious request messages received from an offload server to a desiredWiFi transceivers 703 via a bank of RF switch 713. The desired WiFitransceiver 703 may be determined out of the plurality of WiFitransceivers 703 based on the location of the mobile client device. Inanother embodiment, instead of using the virtual WiFi transceiver 711,the CPU 701 may be configured to directly route the request messages tothe desire WiFi transceiver 703 via a driver interface. For example, asoftware driver may be provided on the CPU 701 to route the requestmessages to the desire WiFi transceiver 703 via a software driverinterface.

In another embodiment, the wireless access point 700 may be used in themobile data offload method for data transmission between the mobileclient device and the access point as described in FIGS. 5 and 6 above.

The plurality of WiFi transceivers 703 may be configured to transmitdownlink data to the mobile client device via the second network.

In an embodiment, the virtual transceiver 711 may be used to fake one ormore packets as if the packets originate from the mobile client device,and to send the faked packets to a desired wireless transceiver 703determined out of the plurality of wireless transceivers 703. Thedesired WiFi transceiver 703 may be determined out of the plurality ofWiFi transceivers 703 based on the location of the mobile client device.The MAC address of the virtual transceiver 711 needs to be modified tomimic the packet that is sent from the distant client device.

In another embodiment, instead of using the virtual WiFi transceiver711, the CPU 701 may be configured to directly generate the requiredmessages/frames, such as CTS and ACK messages, and send the generatedmessages/frames to the desire WiFi transceiver 703 via a driverinterface. For example, a software driver may be provided on the CPU 701to generate and send the required messages/frames via a software driverinterface. This is an alternative method that can be used to mimic therequired transmission from the mobile client.

FIG. 8 shows a schematic diagram of a mobile client device according toan embodiment.

The mobile client device 800 may be implemented by a computer system,and may be used in the offload method of FIGS. 3-6 above. The computersystem may include a CPU 801 (central processing unit), a processor 803,a memory 805, a network interface 807, input interface/devices 809 andoutput interface/devices 811. All the components 801, 803, 805, 807,809, 811 of the computer system 200 are connected and communicating witheach other through a computer bus 813.

The memory 805 may be used as for storing various messages or packetswhich are generated or received by the mobile client device 800according to the method of the embodiments. The memory 805 may includemore than one memory, such as RAM, ROM, EPROM, flash memory, hard disk,etc. wherein some of the memories are used for storing data and programsand other memories are used as working memories.

In an embodiment, the memory 805 may be configured to store instructionsfor the mobile data offload process as described in various embodimentsabove. The instructions, when executed by the CPU 801, may cause the CPU801 to carry out the mobile data offload process as described in variousembodiments above. The instruction may also cause the CPU 801 to storethe various generated/received messages or packets according to themethod of the embodiments in the memory 805.

In another embodiment, the processor 803 may be a special purposeprocessor for executing the instructions described above.

The CPU 801 or the processor 803 may be connected to a network throughthe network interface 807. In an embodiment, the network interface 807may include a first interface providing access to a Cellular Wide Arearadio communication network (e.g. a 3G network) and a second interfaceproviding access to a Short Range radio communication network or aMetropolitan Area System radio communication network (e.g. a WiFinetwork).

The Input 809 may include a keyboard, a touch screen, a mouse, etc. Theoutput 811 may include a display.

In one embodiment, the mobile client device 800 may include atransceiver (not shown) configured to transmit one or more proberequests, authentication requests and/or association requests to awireless access point through the first interface via the Cellular WideArea radio communication network and to transmit the one or morerequests to the wireless access point throught the second interface viathe Short Range radio communication network or the Metropolitan AreaSystem radio communication network, respectively. The transceiver mayalso be configured to receive responses from the wireless access pointthrough the second interface via the Short Range radio communicationnetwork or the Metropolitan Area System radio communication network. Inone embodiment, the transceiver is embedded into the network interface807. The transceiver may also be an external transceiver in anotherembodiment.

In an embodiment, the mobile client device 800 may further include adetermining circuit configured to determine whether the mobile clientdevice 800 receives an association response after the transmission ofthe association request in accordance with the offload method describedabove. The determining circuit may be implemented within the CPU 801 orthe processor 803.

In another embodiment, the transceiver (not shown) may be configured totransmit uplink data to the wireless access point through the firstinterface via the Cellular Wide Area radio communication network, and toreceive downlink data from the wireless access point through the secondinterface via the Short Range radio communication network or theMetropolitan Area System radio communication network.

In a further embodiment, the mobile client device 800 may include aninterception circuit (not shown) configured to intercept uplink data tobe transmitted to the wireless access point via the Short Range radiocommunication network or the Metropolitan Area System radiocommunication networkin accordance with the offload method describedabove. The interception circuit may be implemented within the CPU 801 orthe processor 803.

In accordance with the above embodiment, the mobile client device 800provides an intermediate layer for capturing the packets that arereceived from WiFi and sent out from the mobile device via WiFi. Invarious embodiments, the mobile client device 800 may also be configuredto keep track of the packets that have been received via WiFi, informthe AP about the missing packets and report back via 3G network, splitthe outgoing packets for transmission via 3G network and incomingpackets for transmission via WiFi, selectively route incoming packetsvia 3G, terminate the above special operation mode if the userterminates the application session, and split applications layer,session layer and networking layer protocols such as HTTP and TCP,between the 3G link uplink and WiFi downlink between the mobile clientand the AP. These functions may be implemented as software instructionsstored in the memory 805, or may be implemented as hardware circuits forcarrying out the various functions.

Similar to the mobile client device above, the offload server asdescribed above may also be implemented by a computer system shown inFIG. 8. The transceiver of the offload server may be configured toreceive a probe request, an authentication request and/or an associationrequest from a mobile client device via a Cellular Wide Area radiocommunication network; and to transmit the received probe request, thereceived authentication request and/or the received association requestto a wireless access point via the Cellular Wide Area radiocommunication network.

While the invention has been particularly shown and described withreference to specific embodiments, it should be understood by thoseskilled in the art that various changes in form and detail may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims. The scope of the invention is thusindicated by the appended claims and all changes which come within themeaning and range of equivalency of the claims are therefore intended tobe embraced.

What is claimed is:
 1. A mobile data offload method for associating amobile client device with a wireless access point, the methodcomprising: transmitting a first authentication request from the mobileclient device to the wireless access point via a first network, thefirst network being a Cellular Wide Area radio communication network;transmitting a second authentication request from the mobile clientdevice to the wireless access point via a second network, the secondnetwork being a Short Range radio communication network or aMetropolitan Area System radio communication network; upon receiving atleast one of the first authentication request and the secondauthentication request at the wireless access point, transmitting anauthentication response from the wireless access point to the mobileclient device via the second network; and upon receiving theauthentication response at the mobile client device, associating themobile client device with the wireless access point; whereintransmitting the first authentication request via the first networkcomprises: transmitting the first authentication request from the mobileclient device to an offload server via the first network; andtransmitting the first authentication request from the offload server tothe wireless access point via the first network.
 2. The method of claim1, wherein the sequence of transmitting the first authentication requestand transmitting the second authentication request is interchangeable.3. The method of claim 1, wherein associating the mobile client devicewith the wireless access point comprises: upon receiving theauthentication response at the mobile client, transmitting a firstassociation request from the mobile client device to the wireless accesspoint via the first network; transmitting a second association requestfrom the mobile client device to the wireless access point via thesecond network; upon receiving at least one of the first associationrequest and the second association request at the wireless access point,transmitting an association response from the wireless access point tothe mobile client via the second network.
 4. The method of claim 1,further comprising: after transmitting the authentication response fromthe wireless access point for a predetermined time period, transmittingone or more association responses continuously from the wireless accesspoint to the mobile client via the second network; transmitting anassociation request from the mobile client device to the wireless accesspoint; determining whether the mobile client device receives the one ormore association responses after the transmission of the associationrequest; and associating the mobile client device with the wirelessaccess point, if it is determined that the mobile client device receivesthe one or more association responses after the transmission of theassociation request.
 5. The method of claim 1, further comprising:before transmitting the first authentication request and the secondauthentication request from the mobile client device, transmitting afirst probe request from the mobile client device to the wireless accesspoint via the first network; transmitting a second probe request fromthe mobile client device to the wireless access point via the secondnetwork; and upon receiving at least one of the first probe request andthe second probe request at the wireless access point, transmitting aprobe response from the wireless access point to the mobile client viathe second network.
 6. A wireless access point comprising a plurality ofwireless transceivers, wherein the wireless transceivers are configuredto receive one or more probe requests, authentication requests and/orassociation requests from an offload server via a first network and/orfrom a mobile client device via a second network, and the wirelesstransceivers are configured to transmit a probe response, anauthentication response and/or an association response to the mobileclient device via the second network; wherein the first network is aCellular Wide Area radio communication network, and the second networkis a Short Range radio communication network or a Metropolitan AreaSystem radio communication network; wherein the wireless access pointfurther comprises a virtual wireless transceiver or a driver, thevirtual wireless transceiver or the driver being configured to route theprobe requests, authentication requests and/or association requests to adesired wireless transceiver determined out of the plurality of wirelesstransceivers; and wherein the desired wireless transceiver is determinedbased on the location of mobile client device.
 7. The wireless accesspoint of claim 6, wherein the wireless access point is a long range WiFiaccess point providing a radio range of more than 100 m.
 8. The wirelessaccess point of claim 6, wherein, the virtual wireless transceiver orthe driver is further configured to fake one or more packets as if thepackets originate from the mobile client device, and to send the fakedpackets to the desired wireless transceiver determined out of theplurality of wireless transceivers.
 9. A mobile data offload method,comprising: transmitting uplink data from a mobile client device via afirst network, the first network being a Cellular Wide Area radiocommunication network; and transmitting downlink data to the mobileclient device via a second network, the second network being a ShortRange radio communication network or a Metropolitan Area System radiocommunication network, wherein the method further comprises: initiatingthe transmission of downlink data from a wireless access point to themobile client device using a two-way handshake or a four-way handshake;transmitting a data packet from the wireless access point to the mobileclient device via the second network; faking, at the wireless accesspoint, an ACK packet as if the ACK packet originates from the mobileclient device; sending the ACK packet to a desired wireless transceiverof the wireless access point; before transmitting the data packet,transmitting a RTS (Ready to send) message from the wireless accesspoint to the mobile client device via the second network; faking, at thewireless access point, a CTS (Clear to send) message as if the CTSmessage originates from the mobile client device; and sending the CTSmessage to a desired wireless transceiver of the wireless access point.10. The method of claim 9, further comprising: upon receiving the datapacket at the mobile client device, intercepting transmission of a dataresponse packet from the mobile client device to the wireless accesspoint via the second network; and transmitting the data response packetfrom the mobile client device to the wireless access point via the firstnetwork.
 11. The method of claim 9, further comprising intercepting, atthe mobile client device, the transmission of the uplink data via thesecond network.